- (* We need to remove the out_scope_tags to avoid propagation of
- them that triggers again the ad-hoc case *)
- let subst =
- List.map (fun (i,(tag,ctx,bo,ty)) ->
- let tag =
- List.filter
- (function `InScope | `OutScope _ -> false | _ -> true) tag
- in
- i,(tag,ctx,bo,ty)
- ) subst
- in
- (try
- let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
- let term = eta_reduce status subst term in
- let subst = List.filter (fun (j,_) -> j <> i) subst in
- metasenv, ((i, (name, ctx, term, ty)) :: subst)
- with Not_found -> assert false))
- | NCic.Meta (n, _), _ when is_locked n subst && swap ->
- unify status test_eq_only metasenv subst context t2 t1 false
-
- | t, C.Meta (n,lc) when List.mem_assoc n subst ->
- let _,_,term,_ = NCicUtils.lookup_subst n subst in
- let term = NCicSubstitution.subst_meta status lc term in
- unify status test_eq_only metasenv subst context t term swap
- | C.Meta (n,_), _ when List.mem_assoc n subst ->
- unify status test_eq_only metasenv subst context t2 t1 (not swap)
-
- | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
- let _,_,term,_ = NCicUtils.lookup_subst i subst in
- let term = NCicSubstitution.subst_meta status l term in
- unify status test_eq_only metasenv subst context t1
- (mk_appl status ~upto:(List.length args) term args) swap
- | NCic.Appl (NCic.Meta (i,_)::_), _ when List.mem_assoc i subst ->
- unify status test_eq_only metasenv subst context t2 t1 (not swap)
-
- | C.Meta (n,_), C.Meta (m,lc') when
- let _,cc1,_ = NCicUtils.lookup_meta n metasenv in
- let _,cc2,_ = NCicUtils.lookup_meta m metasenv in
- (n < m && cc1 = cc2) ||
- let len1 = List.length cc1 in
- let len2 = List.length cc2 in
- len2 < len1 && cc2 = fst (HExtlib.split_nth len2 cc1) ->
- instantiate status test_eq_only metasenv subst context m lc'
- (NCicReduction.head_beta_reduce status ~subst t1) (not swap)
- | C.Meta (n,lc), C.Meta (m,lc') when
- let _,_,tyn = NCicUtils.lookup_meta n metasenv in
- let _,_,tym = NCicUtils.lookup_meta m metasenv in
- let tyn = NCicSubstitution.subst_meta status lc tyn in
- let tym = NCicSubstitution.subst_meta status lc tym in
- match tyn,tym with
- NCic.Sort NCic.Type u1, NCic.Sort NCic.Type u2 ->
- NCicEnvironment.universe_lt u1 u2
- | _,_ -> false ->
- instantiate status test_eq_only metasenv subst context m lc'
- (NCicReduction.head_beta_reduce status ~subst t1) (not swap)
- | C.Meta (n,lc), t ->
- instantiate status test_eq_only metasenv subst context n lc
- (NCicReduction.head_beta_reduce status ~subst t) swap
- | t, C.Meta (n,lc) ->
- instantiate status test_eq_only metasenv subst context n lc
- (NCicReduction.head_beta_reduce status ~subst t) (not swap)
-
- (* higher order unification case *)
- | NCic.Appl (NCic.Meta (i,l) as meta :: args), _ ->
- (* this easy_case handles "(? ?) =?= (f a)", same number of
- * args, preferring the instantiation "f" over "\_.f a" for the
- * metavariable in head position. Since the arguments of the meta
- * are flexible, delift would ignore them generating a constant
- * function even in the easy case above *)
- let easy_case =
- match t2 with
- | NCic.Appl (f :: f_args)
- when
- List.exists (NCicMetaSubst.is_flexible status context ~subst) args ->
- let mlen = List.length args in
- let flen = List.length f_args in
- let min_len = min mlen flen in
- let mhe,margs = HExtlib.split_nth (mlen - min_len) args in
- let fhe,fargs = HExtlib.split_nth (flen - min_len) f_args in
- (try
- Some (List.fold_left2
- (fun (m, s) t1 t2 ->
- unify status test_eq_only m s context t1 t2 swap
- ) (metasenv,subst)
- ((NCicUntrusted.mk_appl meta mhe)::margs)
- ((NCicUntrusted.mk_appl f fhe)::fargs))
- with UnificationFailure _ | Uncertain _ | KeepReducing _ ->
- None)
- | _ -> None
+ metasenv, subst, to_restrict, i-1
+ with UnificationFailure _ | Uncertain _ ->
+ metasenv, subst, i::to_restrict, i-1)
+ l1 l2 (metasenv, subst, [], List.length l1)
+ in
+ if to_restrict <> [] then
+ let metasenv, subst, _, _ =
+ NCicMetaSubst.restrict status metasenv subst n1 to_restrict
+ in
+ metasenv, subst
+ else metasenv, subst
+ with
+ | Invalid_argument _ -> assert false
+ | NCicMetaSubst.MetaSubstFailure msg ->
+ try
+ let _,_,term,_ = NCicUtils.lookup_subst n1 subst in
+ let term1 = NCicSubstitution.subst_meta status lc1 term in
+ let term2 = NCicSubstitution.subst_meta status lc2 term in
+ unify status test_eq_only metasenv subst context term1 term2 swap
+ with NCicUtils.Subst_not_found _-> raise (UnificationFailure msg))
+
+ | NCic.Appl (NCic.Meta (i,_)::_ as l1),
+ NCic.Appl (NCic.Meta (j,_)::_ as l2) when i=j ->
+ (try
+ List.fold_left2
+ (fun (metasenv, subst) t1 t2 ->
+ unify status (*test_eq_only*) true metasenv subst context t1
+ t2 swap)
+ (metasenv,subst) l1 l2
+ with Invalid_argument _ ->
+ raise (UnificationFailure (mk_msg status metasenv subst context t1 t2)))
+
+ | _, NCic.Meta (n, _) when is_locked n subst && not swap && not during_delift ->
+ (let (metasenv, subst), i =
+ match NCicReduction.whd status ~subst context t1 with
+ | NCic.Appl (NCic.Meta (i,l) as meta :: args) ->
+ let metasenv, lambda_Mj =
+ lambda_intros status metasenv subst context (List.length args)
+ (NCicTypeChecker.typeof status ~metasenv ~subst context meta)
+ in
+ unify status test_eq_only metasenv subst context
+ (C.Meta (i,l)) lambda_Mj false,
+ i
+ | NCic.Meta (i,_) -> (metasenv, subst), i
+ | _ ->
+ raise (UnificationFailure (lazy "Locked term vs non
+ flexible term; probably not saturated enough yet!"))
+ in
+ let t1 = NCicReduction.whd status ~subst context t1 in
+ let j, lj =
+ match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
+ in
+ let metasenv, subst =
+ instantiate status test_eq_only metasenv subst context j lj t2 true
+ in
+ (* We need to remove the out_scope_tags to avoid propagation of
+ them that triggers again the ad-hoc case *)
+ let subst =
+ List.map (fun (i,(tag,ctx,bo,ty)) ->
+ let tag =
+ List.filter
+ (function `InScope | `OutScope _ -> false | _ -> true) tag
+ in
+ i,(tag,ctx,bo,ty)
+ ) subst
+ in
+ (try
+ let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
+ let term = eta_reduce status subst term in
+ let subst = List.filter (fun (j,_) -> j <> i) subst in
+ metasenv, ((i, (name, ctx, term, ty)) :: subst)
+ with Not_found -> assert false))
+ | NCic.Meta (n, _), _ when is_locked n subst && swap ->
+ fo_unif0 during_delift status false test_eq_only metasenv subst context m2 m1
+
+ | _, C.Meta (n,lc) when List.mem_assoc n subst ->
+ let _,_,term,_ = NCicUtils.lookup_subst n subst in
+ let term = NCicSubstitution.subst_meta status lc term in
+ fo_unif0 during_delift status swap test_eq_only metasenv subst context
+ m1 (false,term)
+ | C.Meta (n,_), _ when List.mem_assoc n subst ->
+ fo_unif0 during_delift status (not swap) test_eq_only metasenv subst context m2 m1
+
+ | _, NCic.Appl (NCic.Meta (i,l)::args) when List.mem_assoc i subst ->
+ let _,_,term,_ = NCicUtils.lookup_subst i subst in
+ let term = NCicSubstitution.subst_meta status l term in
+ fo_unif0 during_delift status swap test_eq_only metasenv subst context
+ m1 (false,mk_appl status ~upto:(List.length args) term args)
+ | NCic.Appl (NCic.Meta (i,_)::_), _ when List.mem_assoc i subst ->
+ fo_unif0 during_delift status (not swap) test_eq_only metasenv subst context m2 m1
+
+ | C.Meta (n,_), C.Meta (m,lc') when
+ let _,cc1,_ = NCicUtils.lookup_meta n metasenv in
+ let _,cc2,_ = NCicUtils.lookup_meta m metasenv in
+ (n < m && cc1 = cc2) ||
+ let len1 = List.length cc1 in
+ let len2 = List.length cc2 in
+ len2 < len1 && cc2 = fst (HExtlib.split_nth len2 cc1) ->
+ instantiate status test_eq_only metasenv subst context m lc'
+ (NCicReduction.head_beta_reduce status ~subst t1) (not swap)
+ | C.Meta (n,lc), C.Meta (m,lc') when
+ let _,_,tyn = NCicUtils.lookup_meta n metasenv in
+ let _,_,tym = NCicUtils.lookup_meta m metasenv in
+ let tyn = NCicSubstitution.subst_meta status lc tyn in
+ let tym = NCicSubstitution.subst_meta status lc tym in
+ match tyn,tym with
+ NCic.Sort NCic.Type u1, NCic.Sort NCic.Type u2 ->
+ NCicEnvironment.universe_lt u1 u2
+ | _,_ -> false ->
+ instantiate status test_eq_only metasenv subst context m lc'
+ (NCicReduction.head_beta_reduce status ~subst t1) (not swap)
+ | C.Meta (n,lc), t ->
+ instantiate status test_eq_only metasenv subst context n lc
+ (NCicReduction.head_beta_reduce status ~subst t) swap
+ | t, C.Meta (n,lc) ->
+ instantiate status test_eq_only metasenv subst context n lc
+ (NCicReduction.head_beta_reduce status ~subst t) (not swap)
+
+ (* higher order unification case *)
+ | NCic.Appl (NCic.Meta (i,l) as meta :: args), _ ->
+ (* this easy_case handles "(? ?) =?= (f a)", same number of
+ * args, preferring the instantiation "f" over "\_.f a" for the
+ * metavariable in head position. Since the arguments of the meta
+ * are flexible, delift would ignore them generating a constant
+ * function even in the easy case above *)
+ let easy_case =
+ match t2 with
+ | NCic.Appl (f :: f_args)
+ when
+ List.exists (NCicMetaSubst.is_flexible status context ~subst) args ->
+ let mlen = List.length args in
+ let flen = List.length f_args in
+ let min_len = min mlen flen in
+ let mhe,margs = HExtlib.split_nth (mlen - min_len) args in
+ let fhe,fargs = HExtlib.split_nth (flen - min_len) f_args in
+ (try
+ Some (List.fold_left2
+ (fun (m, s) t1 t2 ->
+ unify status test_eq_only m s context t1 t2 swap
+ ) (metasenv,subst)
+ ((NCicUntrusted.mk_appl meta mhe)::margs)
+ ((NCicUntrusted.mk_appl f fhe)::fargs))
+ with UnificationFailure _ | Uncertain _ | KeepReducing _ ->
+ None)
+ | _ -> None
+ in
+ (match easy_case with
+ | Some ms -> ms
+ | None ->
+ (* This case handles "(?_f ..ti..) =?= t2", abstracting every
+ * non flexible ti (delift skips local context items that are
+ * flexible) from t2 in two steps:
+ * 1) ?_f := \..xi.. .?
+ * 2) ?_f ..ti.. =?= t2 --unif_machines-->
+ ?_f[..ti..] =?= t2 --instantiate-->
+ delift [..ti..] t2 *)
+ let metasenv, lambda_Mj =
+ lambda_intros status metasenv subst context (List.length args)
+ (NCicTypeChecker.typeof status ~metasenv ~subst context meta)